This invention relates to field-deployable spatial positioning or measurement systems. Specifically, the present invention provides spatial positioning or measurement systems that use novel system hardware, calibration methods and transmission/detection modes to provide increased ease-of-use, better reliability, increased system longevity, easier calibration methods, wider usable range and improved versatility. As such, the spatial positioning or measurement systems according to the various embodiments of the present invention are capable of providing high resolution, reproducible and accurate spatial or position measurements in two or three dimensions thus allowing enhanced accuracy and utility for use in surveying and construction and manufacturing layout. The present invention may also be used for applications including spatial data generation for design of vehicular systems or vector and tensor mapping such as accumulating data relating to temperature, wind shear, electric fields, radiation flux, etc.
Present uses for field-deployable spatial positioning systems include construction layout such as setting reference points or setting control lines, asymptotes and similar geometric boundaries or guide lines; laying out parallel or perpendicular lines; measuring linear distances between points; navigating to specific points entered by a user; and establishing working planes. Such uses may include generation of level or sloped plane references for earthwork and site preparation; generation of vertical (plumb) plane references for tilt-up wall placement; and XY (2-D) or XYZ (3-D) coordinate measurement for positioning concrete forms, footers, and anchor bolts.
Additional uses for field-deployable spatial positioning systems include machine control or robotic applications, and transfer of measurement or spatial positioning data to and from CAD systems or databases.
Prior art field-deployable spatial positioning and measurement systems include those described in U.S. Pat. Nos. 4,874,238; 5,100,229; 5,110,202; 5,579,102; 5,461,473; 5,294,970; and 5,247,487, all of which are hereby incorporated by reference in their entirety. Spatial positioning systems described in these patent references usually comprise a single xe2x80x9claser transmitterxe2x80x9d and a single xe2x80x9claser receiverxe2x80x9d. The transmitter is placed at a fixed location and serves as a measurement reference or beacon for the receiver. The handheld receiver is carried by the user and displays in real-time the location of the receiver relative to the transmitter. Because of mathematical constraints, such a single-transmitter system is only capable of measuring the horizontal (azimuth) and vertical (elevation) angular location of the receiver; that is, no direct measurement of the range from the transmitter to receiver is possible. A more advanced system consists of two or more transmitters and a single receiver. The transmitters are again placed at fixed locations, and serve the same purpose as before. The receiver calculates its azimuth and elevation location relative to each transmitter. If the transmitters are at known locations, the receiver can then calculate its position in 3-D space using known methods and algorithms, e.g., see U.S. Pat. No. 5,100,229 as cited above. In either the single or multi-transmitter systems, multiple receivers may be used simultaneously with the same transmitter(s). This is possible since the transmitters only serve as a reference or beacon, in the same way that GPS satellites serve as a reference for many users. Calculations to determine the location of a given receiver take place in that receiver, not the transmitter(s).
As will be described more fully below, the primary components of a transmitter can include the following: a rotary laser head containing two laser assemblies; a spindle assembly including a motor and encoder for spinning the rotary laser head; an optical strobe assembly that functions as an azimuth reference to establish a xe2x80x9czeroxe2x80x9d angle for the azimuth angle; a gimbal assembly including level sensors and motors for leveling the rotary laser head; and control electronics needed to perform various functions including sensing, balancing, monitoring, position determination, user interfacing and data output. The rotary laser head contains two laser assemblies that produce two fanned infrared laser beams perpendicular to the spin axis of the head as described in the above-reference U.S. patents. The radial axes of the fan beams can be chosen to be separated by approximately 90 degrees (or other angle) around the head. The fan beams are also rotated approximately 30 degrees in opposite directions about their respective radial axes.
The rotating laser head is attached to the top end of a shaft through the spindle assembly. The lower end of the shaft is attached to a motor and rotary encoder. The motor spins the shaft, and thus the head at a known constant speed. The rotary encoder is used to sense the rotation speed of the shaft and provides feedback to the motor drive circuit in the control electronics.
As is described in the above-reference U.S. patents, an optical strobe assembly can be used to synchronize, or set a rotation datum for, the azimuthal angle swept by the fanned beams. This can be implemented as a ring of outward-facing IREDs (infrared emitting diodes) located just below the rotating laser head. The strobe is stationary, and mounted to the outside of the spindle assembly. Using feedback from the rotary encoder on the shaft, the control electronics cause the strobe to emit a very short flash of infrared light once per revolution of the head, or any other set interval. This flash is detected by the mobile receiver and used as a zero azimuth angle reference.
The gimbal assembly is attached to the outside of the spindle assembly, and connects it to the outer housing of the transmitter. The purpose of the gimbal assembly is to allow a tilt (in two axes) in a known manner of the rotary head spin axis relative to the outer housing. In most applications it is desirable, for reasons to be explained below, to plumb the spin axis of the head with respect to gravity (or to some other desired axis). If this is done, the radial axes of the fan lasers, which are perpendicular to the spin axis, will sweep through a plane that is level with respect to gravity. In order to plumb the spin axis, the control electronics reads the output of the level sensors, which are attached to the outside of the spindle assembly, and drives the motors of the gimbal assembly until the sensor outputs indicate that the spin axis is plumb. Well known electrolytic vials can be used as monitors in assisting this feedback function.
Control electronics govern the overall operation of the laser transmitter. As mentioned above, the electronics control the rotation speed of the head by using the rotary encoder output as feedback. The electronics further trigger the optical strobe once per revolution of the head and plumbs the spin axis by moving the gimbal assembly based on feedback from the level sensors.
The primary components of the receiver generally include the following: a detector such as a (photodiode) assembly for sensing the optical strobe and fan lasers from the transmitter(s); timing electronics for measuring the time between received pulses; a processor, such as a microprocessor, for calculating the location of the receiver; and a user interface such as a display and keypad. The detector or photodiode assembly produces an electrical output in response to the optical strobe signal from the transmitter(s). The detector or photodiode assembly also produces an output pulse whenever crossed by one of the rotating fan beams from a transmitter. For example, when the detector is in the vicinity of a single transmitter, the output for one complete rotation of the transmitter head can include times T1, T2, and Trev measured by timing electronics, where T1 is the time between a (received) strobe light pulse and a first fanned laser beam; T2 is the time between a strobe light pulse and a second fanned laser beam; and Trev is the time between strobe pulses.
The microprocessor calculates the angular location of the receiver relative to the transmitter by using the output of the timing electronics. Since the strobe is omnidirectional, the absolute time at which the strobe pulse is received is independent of the position of the receiver. The two fan beams projected from the transmitter are tipped 30 degrees in opposite directions about their radial axes, which are separated by 90 degrees about the rotating laser head. Therefore the elevation (vertical) angle of the receiver relative to the transmitter will be a function of the time between the received laser pulses, and the azimuth (horizontal) angle will be a function of the average time from the strobe to the two laser pulses as given, for example, in U.S. Pat. No. 5,110,202 cited above. If the speed of rotation of the transmitter head is very steady, the angular position of the receiver may be calculated as:
azimuth angle=360*(T1 +T2)/(2*Trev)xe2x80x83xe2x80x83Eqn. 1
                              elevation          ⁢                      xe2x80x83                    ⁢          angle                =                                                            360                *                                                      (                                          T1                      +                      T2                                        )                                    /                  Trev                                            -              90                        2                    *                      cot            ⁡                          (              30              )                                                          Eqn        .                  xe2x80x83                ⁢        2            
The result of these calculations is output in various formats on the display, depending on the particular application. The keypad allows the user to control the operating mode.
One aspect of such a spatial positioning system is the use of a length standard to set a scale for the spatial positioning system because the above scheme often measures the azimuthal and elevation angles only, depending on the number of transmitters and the system functions selected. With a single detector and transmitter, for example, the distance between the two is unknown. One method of estimating the distance is to perform a xe2x80x9cstadia measurementxe2x80x9d, which is a common technique in surveying. This measurement can be performed with two detectors (such as photodiodes) mounted to a straight rod a known distance apart (e.g., 2 meters). Both detectors would be connected to the same receiver, which would then simultaneously calculate the angular position of each detector relative to the transmitter. Since the distance between the detectors is known, the receiver can make a relatively crude estimate of the distance from the rod to the transmitter. This method is suitable if highly accurate measurements are not required, but suffers from parallax type error, especially over long ranges in the field of measurement.
If more accuracy is required, a multi-transmitter system may be used. This system is capable of calculating accurate 2-dimensional or 3-dimensional positions of a single-detector receiver. The basic measurement is the same as in the single-transmitter system; that is, the receiver calculates its angular location relative to each transmitter. Mathematically, the location of the receiver relative to a given transmitter is somewhere along a vector that starts at the transmitter and passes through the receiver. If the transmitters are at known locations, then solving for the intersection of the vectors extending from each transmitter to the receiver will give coordinates of the receiver. More precisely, the coordinates found are at the center of the detector or photodiode.
However, for systems using only one transmitter or for systems using multiple transmitters where increased accuracy and resolution is desired, a scaling reference is needed. One usually introduces a linear scale or distance reference into a known setup procedure for this purpose. Since the basic measurements made are all angular, and the transmitters and setup points are at arbitrary locations, inherent scale in the system can be obtained by several means. For example, a scale bar or tape measure can be used. When, for example, the user measures a point at each end of an object that is exactly one meter long and the receiver is told that the distance between these points is one meter; then the receiver can adjust the scale of the relative coordinate system to give measurements in meaningful units such as meters, inches, feet, etc. The measurement of this scale reference object must be done very accurately, since the operating distance multiplies any error in the scale reference. That is, if a 1 mm error is made in measuring a 1 m scale reference, then the absolute position error at a distance of 50 m is 50 mm. Therefore it is desirable to use long scale references, such as a 10 meter scale reference.
A second aspect for such a spatial positioning system, particularly if it is to be field-deployable, is that contaminants are kept out of certain critical areas containing vital components like the spindle shaft and shaft bearings.
A third aspect for the spatial positioning system is the desirability of a leveled transmitter to enhance the accuracy of the measurements that are made. With the automatic leveling described above, there is still a need for frequent and continued calibration of such leveling in the transmitter units. This calibration is vital for accuracy and usability. From the outset, initial manufacturing tolerances must be set before new transmitters are sold. Transmitters that are dropped, or subject to excessive mechanical vibration should preferably be re-calibrated, and six month periodic calibration are usually recommended and expected. Calibrations are also often required after removal and replacement of mechanical components such as the rotating laser head or spindle assembly. Finally, preparation and certification of a used transmitter for sale would require close calibration of the auto-leveling system.
A fourth aspect of such a spatial positioning system is that the output light or energy from the strobes used to synchronize the azimuthal fan sweep should preferably cover the field of measurement and be of sufficient strength to be detected without ambiguity and with a high enough signal to noise ratio in the control or sensing electronics.
A fifth aspect of such a spatial positioning system is that fiduciary volume over which the transmitter-receiver combination can function should preferably cover the desired field of measurement, such as when doing spatial positioning of tall or high structures.
In the prior art, there are problems associated with each of these requirements.
The first aspect of setting a scale is made difficult by halving to measure a ruler, tape, or other reference in the field. Accuracy can suffer, as noted above, due to measurement errors. Reproducibility can suffer from using different length standards, or using the same standard, but with slightly different deployment, such as when a tape measure is not pulled to the same tightness from measurement to measurement.
The second aspect for keeping contaminants out of selected areas or away from critical components in the transmitter has not been adequately addressed. Typically one uses rotary seals, which introduce friction associated with spinning the rotating laser head. This added friction can reduce battery life in the transmitter. Rotary seals also introduce vibrations and shaft wobble, that, while subtle, can affect accuracy and reproducibility for coordinate measurements, especially over a large field of measurement. Degradation of such rotary seals can reduce system longevity and can send bits of elastomer or other debris into the protected areas, and can release trapped dirt as well.
The third aspect for a calibration of the automatic leveling in a transmitter is quite onerous, and requires use of known elaborate procedures using measurement stands, sensors, and the like. Such present calibrations are very time consuming, and require the laser output to be painstakingly and manually compared to benchmarks and references in a setup stand. This can take hours per unit, and drives up costs. Careful work is required, and setup errors are not well tolerated, resulting in overall calibration errors.
The fourth aspect for strobe or synchronization distribution suffers from severe tradeoffs in usable range and signal strength. Light emitting devices that have narrow solid-angle output distributions that are suitable for long distance xe2x80x9creachingxe2x80x9d of the strobe beam to far locations in the field of measurement are inadequate for measurements close to the transmitter, especially down low or up high. Conversely, light emitting devices that have wide solid-angle output distributions that are suitable for good wide coverage of measurement very close to the transmitter are inadequate for measurements far from the transmitter, because their output intensity drops rapidly as a function of distance from the strobe.
The fifth aspect of keeping a large usable range for vertical types of measurements cannot be addressed with present fanned beam transmitters because the divergence or extent of the fan beams used are not sufficient to cover the entire field of measurement, and can suffer from xe2x80x9cfringexe2x80x9d effects where the crispness or quality of the beam fans degrades at large divergence angles. When the usable range of measurement over the field of measurement suffers because the working space or fiduciary volume subtended by the capabilities of spatial positioning system operation is limited, such as when working in the vertically extended environments, the system cannot be used. Such conditions come up often, such as when tilting pre-fabricated walls to a vertical position. Conventional spatial positioning systems cannot span the necessary vertical fiduciary volume over which accurate measurements must be made, unless a transmitter dedicated to laser sweeps in a vertical plane is used.
It is therefore an object of this invention to provide a field-deployable length standard that is built into the spatial positioning system receiver with capability to reproduce faithfully the force loading of the length standard for greater accuracy. It is also an object to provide protection against contaminant entry without the use of rotary seals or other conventional means used in the spatial positioning system field that have not met with great success without the drawbacks mentioned. It is a further object of this invention to provide a method of calibration the leveling of a transmitter which is easy to implement, accurate, and tolerant of setup errors. It is yet a further object of this invention to provide a scheme for synchronization strobe beam distribution which maximizes usable range for both near and far measurements with respect to the transmitter. It is another object of this invention to provide a way to use the same transmitter for vertical types of measurements, while allowing use of the same control electronics and calibration procedures as cited in the third requirement above. Other objects will become apparent upon reading of the specification.
One general embodiment disclosed includes a transmitter and spatial positioning receiver for a spatial positioning system. The transmitter comprises a stationary portion and a rotating laser head in proximity to the stationary portion. The rotating laser head comprises a first light emitting device operatively configured to emit a divergent rotating light fan onto a field of measurement. The transmitter also comprises a synchronization strobe operatively configured to provide a synchronization strobe beam. The spatial positioning receiver also includes a detector operatively configured to detect the divergent rotating light fan and also the synchronization strobe beam when the spatial positioning receiver is operating in the field of measurement. Additionally, the system also includes a processor programmably configured to determine at least one spatial coordinate of the detector in the spatial positioning receiver based on a time of receipt of at least one of the divergent rotating light fan and the synchronization strobe beam from the transmitter.
The transmitter and spatial positioning receiver also comprise a field-deployable length standard for use with the spatial positioning receiver for spatial position-marking, setting, calibrating or referencing in the spatial positioning system. This field-deployable length standard comprises a reelable tape comprising at least one markable position. The reelable tape and the markable position are each positioned and oriented with respect to the spatial positioning receiver such that when the spatial positioning receiver is moved from a first location to a second location and upon unreeling the reelable tape and using the markable position, a detector in the spatial positioning receiver is a known distance from the first location of the detector in the spatial positioning receiver prior to unreeling the reelable tape.
Additionally, the transmitter is so constructed so that the stationary portion and the rotating laser head are each individually positioned, shaped, and oriented such that there is defined an interface volume therebetween. The transmitter then further comprises a labyrinth seal, so sized, positioned and oriented so as to restrict the motion of contaminants through the interface volume between the rotating laser head and the stationary portion of the transmitter.
Additionally, there is found a strobe set to provide a spatial positioning transmitter synchronization strobe beam to improve energy distribution and operating range when communicating with the spatial positioning receiver operating in the field of measurement. The strobe set further comprises a first strobe having an output distribution of a first value for half power beam angular width, oriented to provide output onto the field of measurement. A second strobe is provided having an output distribution of a second value for half power beam width higher than the first value for half power beam angular width, oriented to provide output onto the field of measurement. The first and second strobes are further positioned and oriented such that the operating range of the spatial positioning receiver is increased with respect to the first and second strobes both having either the first value or the second value for half power beam angular width. The transmitter can also comprise a sensor to sense when the transmitter is oriented so as to sweep the divergent rotating light fan in a substantially vertical plane, with the sensor communicating the sense to the processor for a vertical coordinate determination.
Other embodiments of the inventions described herein will be described below, and individually, some embodiments have only some of the elements thus far cited. For example, we disclose a field-deployable length standard for use with a spatial positioning receiver for spatial position-marking, setting, calibrating or referencing in a spatial positioning system, the field-deployable length standard comprising a reelable tape comprising at least one markable position. The reelable tape and the markable position are each so positioned and oriented with respect to the spatial positioning receiver such that when the spatial positioning receiver is moved from a first location to a second location, and upon unreeling the reelable tape and using the markable position, a detector in the spatial positioning receiver is a known distance from the first location of the detector in the spatial positioning receiver prior to unreeling the reelable tape. Additionally, the markable position can comprise a detent operative upon the reelable tape.
Alternatively, the field deployable length standard can comprise a reelable tape reeled upon a reel assembly in mechanical communication with a housing. This reel assembly can optionally be under a spring bias with respect to the housing so as to allow movement of the reel assembly with respect to the housing. The spring bias can optionally allow for a desired force loading along the reelable tape. The housing can also comprise an aperture so shaped, sized, positioned, and oriented so as to allow a viewing of the movement of the reel assembly, with the viewing operative to allow a calibration of the force loading along the reelable tape. Alternatively, the aperture can comprise a lens so shaped, sized, positioned and oriented so as to allow viewing of the movement of the reel assembly, with the viewing through the lens operative to allow a similar calibration of the force loading along said reelable tape.
Another embodiment can comprise a field-deployable length standard for use with a spatial positioning receiver for spatial position-marking, setting, calibrating or referencing in a spatial positioning system, with the field-deployable length standard comprising a reelable tape in mechanical communication with the spatial positioning receiver. The reelable tape comprises a first markable position, and a second markable position a known path length along the reelable tape from the first markable position when the reelable tape is unreeled. The first and second markable positions can be so positioned and oriented with respect to the spatial positioning receiver when the reelable tape is unreeled such that when the spatial positioning receiver is posed to a first location upon unreeling the reelable tape and using the first markable position, a detector in the spatial positioning receiver is a known distance with respect to the detector when the spatial positioning receiver is posed to a second location upon unreeling the reelable tape and using the second markable position of the reelable tape. In turn, any of the first and second markable positions can comprise a detent operative upon the reelable tape. Optionally, the reelable tape for this embodiment can be reeled upon a reel assembly in mechanical communication with a housing.
Additionally, the reel assembly can be under an optional spring bias with respect to the housing so as to allow movement of the reel assembly with respect to the housing. Optionally, this spring bias can allow for a desired force loading along the reelable tape. And, as before, the housing can comprise an aperture so shaped, sized, positioned, and oriented so as to allow a viewing of the movement of the reel assembly, with the viewing operative to allow a calibration of the force loading along the reelable tape. Again, the aperture can optionally comprise a lens so shaped, sized, positioned and oriented so as to allow the viewing of the movement of the reel assembly, with the viewing again operative to allow a calibration of the force loading along the reelable tape.
Further embodiments include a transmitter for a spatial positioning system, with the transmitter having a stationary portion and a rotating laser head in proximity to the stationary portion, the stationary portion and the rotating laser head each individually positioned, shaped, and oriented such that there is defined an interface volume therebetween. The transmitter further comprises a labyrinth seal, so sized, positioned and oriented so as to restrict the motion of contaminants through the interface volume between the rotating laser head and the stationary portion of the transmitter. The labyrinth seal can optionally be so formed that a necessary path for any contaminants is serpentine, or, in the alternative, substantially straight. Optionally, the stationary portion and the rotating laser head can each be individually positioned, shaped, and oriented such that the labyrinth seal is formed by at least a portion of either or both of the stationary portion and the rotating laser head, with the labyrinth seal operative in the interface volume. Alternatively, the stationary portion and the rotating laser head can comprise a rotary transformer positioned proximate the interface volume where the rotary transformer is positioned, shaped, and oriented such that the labyrinth seal is formed by at least a portion of the rotary transformer, with the labyrinth seal again operative in the interface volume.
Also disclosed is a method for dynamic leveling of a rotating body to bring a rotational axis of the rotating body into better alignment with a desired axis. This is useful for maintaining functionality and accuracy of the rotating elements used in the systems described. The method comprises:
[a] Aligning an operating axis of an autocollimator to the desired axis, with the autocollimator designed to output a light ray along the operating axis, and the desired axis as a result of the aligning, and to monitor any reflected light rays from the light ray with respect to the desired axis;
[b] affixing a mirror to the rotating body;
[c] orienting the rotating body to within the field of view of the autocollimator;
[d] noting the position of the reflected light rays monitored by the autocollimator, whereby a circular arc is formed by the reflected light rays;
[e] determining the direction and magnitude of a deviation of a geometric center of the circular arc from the operating axis of the autocollimator;
[f] changing the orientation of the rotating body in such a manner so as to bring the rotational axis into better alignment with the operating axis of the autocollimator, whereby the rotational axis will be put into better alignment with the desired axis.
If desired, the desired axis can be a downward gravitational vector. As contemplated here, one can certainly make the rotating body be a rotating laser head in a spatial positioning system. Optionally, too, the mirror can be affixed to the rotating laser head in such a manner that a normal axis of the mirror is substantially parallel with the desired axis. Alternatively, the mirror can be affixed to the rotating laser head in such a manner that a normal axis of the mirror is within 90 degrees of the desired axis.
There is also disclosed a method for forming a spatial positioning transmitter synchronization strobe beam to improve energy distribution and operating range when communicating with a spatial positioning receiver operating in a field of measurement, the method comprising:
[a] arraying a first strobe having an output distribution of a first value for half power beam angular width onto the field of measurement;
[b] arraying a second strobe having an output distribution of a second value for half power beam width higher than the first value for half power beam angular width, onto the field of measurement;
[c] the first and second strobes further positioned and oriented such that the operating range of the spatial positioning receiver is increased with respect to the first and second strobes both having either the first value or the second value for half power beam angular width.
Optionally, the first value for half power angular beam width can be less than 15 degrees, and/or the second value for half power angular beam width can be more than 20 degrees. Also, a plurality of first strobes can be arrayed about a single second strobe, for output of the beam onto the field of measurement. Such a plurality can also be numerically three, as opposed to two or four. In another embodiment, the plurality of first strobes and a plurality of second strobes can be optionally arrayed in such a manner and orientation that each strobe of such first and second strobes is aimed at a distinct direction onto the field of measurement.
In the same vein, one can also optionally select a strobe set to provide a spatial positioning transmitter synchronization strobe beam to improve energy distribution and operating range when communicating with a spatial positioning receiver operating in a field of measurement, with the strobe set comprising a first strobe having an output distribution of a first value for half power beam angular width, oriented to provide output onto the field of measurement; a second strobe having an output distribution of a second value for half power beam width higher than the first value for half power beam angular width, oriented to provide output onto the field of measurement; with the first and second strobes further positioned and oriented such that the operating range of the spatial positioning receiver is increased with respect to the first and second strobes both having either the first value or the second value for half power beam angular width, which achieves one of many objectives sought in the instant teachings. Using this prescription, the first value for half power angular beam width can again be less than 15 degrees, and the second value for half power angular beam width can also be more than 20 degrees. Another embodiment allows that a plurality of first strobes are arrayed about a single second strobe, for output of the beam onto the field of measurement; optionally the plurality can be numerically three. Optionally, the plurality of first strobes and a plurality of second strobes are arrayed in such a manner and orientation that each strobe of such first and second strobes is aimed at a distinct direction onto the field of measurement.
Another embodiment of the instant teachings yields a transmitter and spatial positioning receiver for a spatial positioning system, with the system capable of switching from a horizontal mode to a vertical mode. That system comprises a stationary portion and a rotating laser head in proximity to the stationary portion, with the rotating laser head further comprising a first light emitting device emitting a divergent rotating light fan onto a field of measurement; a synchronization strobe providing a synchronization strobe beam for communicating with the spatial positioning receiver operating in the field of measurement; a detector in the spatial positioning receiver to detect the divergent rotating light fan and also the synchronization strobe beam; and a processor to determine at least one spatial coordinate of the detector in the spatial positioning receiver based on a time of receipt of the divergent rotating light fan and the synchronization strobe beam. The transmitter and spatial positioning receiver also comprise a sensor to sense when the transmitter is oriented so as to sweep the divergent rotating light fan in a substantially vertical plane, the sensor communicating this directionality or sense to the processor for a vertical coordinate determination.
Another embodiment includes various elements, such as a field-deployable spatial positioning transmitter and receiver for spatial position-marking, setting, calibrating or referencing, where the field-deployable spatial positioning transmitter and receiver comprise a transmitter kit comprising a rotating laser head emitting an angled fan of light, where angled can mean that the fan is neither orthogonal nor parallel to the plane through which the head rotates, and a strobe emitter that emits a light pulse in predetermined or programmed relation to the position of the laser head; a processor in data communication with a receiver; with the receiver adapted to be moved about a field of measurement and determine, in conjunction with the processor, distance and orientation. The receiver comprises a light detector, and the receiver determines distance and orientation to the transmitter based on the timing of detections of light from the fan of light and from the strobe.
The receiver can optionally further comprise a field-deployable length standard. Such a standard can comprise a reelable tape that in turn comprises at least one markable position and a reel attached to or incorporated within a housing for the receiver, the reelable tape and the markable position each so positioned and oriented with respect to the receiver such that when the receiver is posed at a first location and then, upon unreeling the reelable tape and using the markable position, a second location, the processor makes its calculations using light detections at the first location and second location, and a known distance provided by the reelable tape. The processor can optionally be attached to or incorporated within the receiver housing. Alternatively, the rotating laser head and strobe emitter can be incorporated into or attached to a common transmitter housing.
General embodiments include a transmitter for a spatial positioning system comprising a transmitter having a portion adapted to be stationary during operation and a rotating laser head mounted on the stationary portion; and a labyrinth seal between the rotating laser head and the stationary portion effective to restrict the motion of contaminants between the rotating laser head and the stationary portion.
Another embodiment includes method for forming a spatial positioning transmitter synchronization strobe beam to improve energy distribution and operating range when communicating with a spatial positioning receiver operating in a field of measurement, the method comprising:
operating a rotating a laser head emitting an angled fan of light
periodically operating, in connection with defined rotations of the laser head, a first strobe having an output distribution of a first value for half power beam angular width onto the field of measurement; and
periodically operating, in connection with defined rotations of the laser head, a second strobe having an output distribution of a second value for half power beam width higher than the first value for half power beam angular width, onto the field of measurement.
In kit form, another possible embodiment includes a spatial positioning system, with the system capable of switching between a horizontal and a vertical mode. This system comprises a transmitter kit and a receiver kit. The transmitter kit comprises a rotating laser head emitting an angled fan of light; a transmitter processor; a strobe emitter that emits a light pulse in predetermined or programmed relation to the position of the laser head; and a sensor to sense when a housing containing the rotating laser head is oriented so as to sweep in a substantially vertical plane and communicate this information to the transmitter processor. The receiver kit comprises a receiver processor in data communication with a receiver. The receiver processor can optionally be the same as the transmitter processor. The receiver is adapted to be moved about a field of operation and determine, in conjunction with the receiver processor, distance and orientation. The receiver comprises a light detector and is adapted such that the receiver determining distance and orientation to the transmitter are based on the timing of detections of light from the fan of light and from the strobe. The transmitter processor signals the receiver processor of the orientation or modulates the transmitter kit light emissions or rotation in a manner detectable by the receiver kit.